Originally Posted by

**princessp** The question is find the limit as x approaches infinity, of x(e^{1/}^{x} -1)

The solution involves letting y = 1/x, however when substituting this in, the limit becomes x approaches 0.

[b]No, as x approaches infinity, 1/x approaches 0 while staying positive. But y = 1/x, so it is y that is approaching 0 from the right,

that is, $\displaystyle 0^+$.

What's the rules with changing the value approaching when substituting in limits, as this is not the first time I have seen this.